Process for the manufacture of white lead.



. 871,947. PATENTED NOV, 26, 1907.

F. W. MORRIS.

PROCESS FOR THE MANUFAGTURE OF WHITE LEAD.

APPLICATION FILED DEO.28.1906.

FRANK W. MORRIS, 0F VICTORIA, BRITISH COLUMBIA, CANADA.

IEOCESS FOR TEE MANUFACTURE OF WHITE LEAD.

are 871,947.

Specification of Letters Patent.

Patented Nov. 26, i907.

Application lcd December Z8. 1906. Serial No. 349.828.

To all whom it 'may concern.'

Bc it known that I, FRANK W. MORRIS, a citizen of the Dominion of Canada, residing at Victoria, in the Province of British Columbia, Canada, have invented a new and useful Improvement in a Process for the Manufacture of IlVhte Lead, of which the following is a s ecication. l

his invention relates to an improved process for manufacturing carbonate of lead er the hydrated carbonate of lead which orms'the white lead 'of commerce.

The invention is full described in the' Jl- "loving specification re erence being made to the' drawing by which it is accompanied, in which: is shown a vertical section through a particular form of electrolytic tank generally suited to th( requirements of the irst part of the recess.

The cell represented in the drawing is one known as the Cactner Kellner, wherein the body of the tank or coll is divided by a vertical'partition 2 into two compartments 3 and 4. The partition does not extend' quite to the bottom where a passage 5 is left, but this passage is sealed against the admixture of the contents of the two compartments by a body of mercury 9.

The tank and the partition is made of such material as will resist attack by the Aelectrof lyte used or any of the products therefrom during thc process.

lloti compartments of the tank are illcd with a solution oi' a formate of a salt of one of the alkali metals, sodium orpotassium, which forms the cicctrolytc. 'lhis formate may be produced by any approved method which need not be here dcscribcd as it i'orms no material part ol thc invention.

in onc com|u1rtmcnt Il is an anode plate (i of metallic lc.nl and in the other 4 a cathode plate 7 oi thc same material to which plates, are connecte thel positive and negative wires o'l' nn electric circuit.

Un a current being passed through 'the electrolyte the l'ornmlc is broken. up and formic acid is produced in the com nn'tment 3 of the anod(I and caustic. soda and hydrogen in the com )artmcnt fl ol` the cathode. 'lhe formic acid attacks the metal of the anode plate (i and produces lead formate inthe anode com )artment 3 and spongy lead and caustic sod1 the. cathode compartimmt 4. rlhe electric current iis now cut oil' and the spongy lead shoveled from the cathode compartment 4 a or caustic potash is formed in into the anode compartment 3 where it is dissolved by the remaining lrce formic acid, and produces lead formate.

The presence of the formic acid which dissolves the lead, but does not alter the mercury prevents the amalgamation of the spongy lead with the mercury.

Applicant might further mention that in the practical a plication of this invention the spongy lea is only produced when the density of thelcurrent 1s in excess of what is required, and that when the current density 1s properly proportioned to the immersed area o, the e ectrode the spongy lead is not produced at all, er if it is, it is at once dissolved by the formic acid of the electrolyte and forms the desired product formate of lead; thus when` the current strength is properly p'ro ortioned very little spongy lead is formed, )ut when t-lu. current strength is in excess then the spongy lead formed is shoveled over into the anode compartment, as heretofore stated, where it comes in contact with an excess. of iormic acid. This lead formate is siphoned out of the anode division into a tank where it is associated with an alkali carbonate such as ammonium carbonatc causing the recipitation of carbonate of lead, which as tiie desiredprmluct is allowed to settle in the bottom of the tankI the ammonium formate being drawn oil as a valuable by-product for subsequent treatment.

The carbonate of lead thus produced is substantially pure and will serve all the requirements rfor which the hydrated carhonate, or white lead of commerce, is at present used; but if hydrated carbonate is required ammonium hydrate is associated with the ammonium carbonate in the required pro iortion in the settling tank, when a hydrated carbonate of lead is precipitated instead ol' a pure carbonate..

llaving now particularly described my invention and the manner ol ils operation, l hereby declare that what/l claim as new and desire to be protected in by Letters latont isz' l. As a )recess l'or the production ol white lead, the i'ormation ol i'ormie acid by elec.- trolytic action on a solution ol' a tornmle ol' one oll the alkali metals, the addition ol' lead to the formic acid whereby l'ornmte ol' lead is produced and thc addition to the l'ormate of lead oll an alkali carbonate.

3. As a process l'or the production of white lead, the formation of formic acid end spongy lead by electrolytic action, keeping said/ formic acid andv spongy lead normally separated, then adding the spongy lead to the formic acid and then precipitating lead carhonate from the lead formate so produced by the addition thereto of any alkali carbonate.l

3. As a process for the production of White lead, the formation lof formic acid and spongy lead by electrolytic action on a solution ci a formate of sodium as an electrolyte, and in the resence of an anode and cathode vof metalic lead,maintaining said anode and cathode separated, and means for maintaining the anode and cathode roducts separated the addition of spongy ead formed at the cathode,`to the formic acid 'formed at the anode, and the precipitation of carbonate of lead from the formate of lead so produced by the addition thereto of ammonium carbonate.

4*. A rocess of the character stated ccnsisting in acting upon metallic lead in the presence of a suitable electrolyte,- si1nulta neously producing lead-formate and spongy sisting 1n acting upon metallic lead in the presence of a suitable electrolyte, simultaneously producing lead-formate and spongy lead Wliile'maintaining the spongy lead and lead=formate separated, simultaneously `producing formic acid in the electrolyte, "then treating -the 'spongy lead With orm'ic acid to produce dead-formate substantially asspecf` 45 lied. f

7. A process of sisting in acting upon metallic lead inHthe presenceof a suitable electrolyte, simultaneously producing lead-formate and spongy lead 4While maintaining the spongy leadand lead-formate separated, simultaneously producing formic acid in the electrolyteftlien treating the s ongy lead With formic acid to produce lead'- lormate, then treating the le'adfA 5 formate With an alkali carbonate to produce carbonate of lead substantially as. specified'.

In testimony whereof. I have signed my name tothis specification in the presence of l twov subscribing `Witnesses.

FRANK [Wl MRRIS.

lJOHN B. HNKR, t

J. J. BAIRD.

electrolyte, 35

the character statedfcoifl-l 

